Disk cleanup prob?

Hi I'm running a windows XP (Home) laptop and recently disk cleanup has been having a problem, it starts and the progress bar just sits there, i have left it for (at times) upto 20 minutes but all this results in is the fans swirly rapidly (because disk cleanup is running 100% processor power). Plus when u try to stop cleanup using the cancle button it remains actively running as a process (still using 100% processor power)